Center for High Angular Resolution Astronomy (CHARA)

The flagship project of Georgia State University's Center for High Angular Resolution Astronomy (CHARA) is its optical/interferometric array of six telescopes located on Mount Wilson. CHARA research is focused on the application of astronomical long-baseline optical/infrared interferometry to high resolution observations leading to the determination of the astrophysical properties of stars. The Center operates the CHARA Array, a six-telescope optical/infrared interferometric array on Mount Wilson, California.

Photo: facilities of the CHARA Array intermingled with the
existing facilities of historic Mount Wilson Observatory.

The CHARA Array is among the most powerful facilities of its kind in the world for studying stars and stellar systems at resolutions not previously available. Among the Array's "firsts" are:

First direct detection of gravity darkening on a single star (Regulus),

First direct measurement of the "P-factor" in the Baade-Wesselink method (δ Cep),

First detection of hot exozodiacal dust around a main-sequence star (Vega)

First model-independent measurement of an exoplanet diameter (HD 189733b),

First angular diameter for a halo population star (μ Cas),

First image of a single, main-sequence star (Altair),

First direct image of an interacting binary (β Lyr), and

Shortest period binary star system yet resolved (σ2 CrB - 1.14 days).

Built with funds from the National Science Foundation, Georgia State University, the W. M. Keck Foundation, and the David and Lucile Packard Foundation, ground was broken on July 13, 1996 at historic Mount Wilson Observatory. The facility was dedicated on October 4, 2000, and "first fringes," which demonstrated the technical feasibilty of CHARA's design, were obtained on September 19, 2001. Another three years of installation was required before the Array became fully operational in 2004, and routine, scheduled observing began in the spring of 2005.

Center for High Angular Resolution Astronomy (CHARA) - OverviewLast Updated on 2009-08-25 00:00:00
The flagship project of Georgia State University's Center for High Angular Resolution Astronomy (CHARA) is its optical/interferometric array of six telescopes located on Mount Wilson. Each telescope of the CHARA Array has a light-collecting mirror 1-meter in diameter. The telescopes are dispersed over the mountain to provide a two-dimensional layout that provides the resolving capability (but not the light collecting ability!) of a single telescope a fifth of a mile in diameter. CHARA is funded by the National Science Foundation, Georgia State University, the W.M. Keck Foundation, and the David and Lucile Packard Foundation.
Light from the individual telescopes is conveyed through vacuum tubes to a central Beam Synthesis Facility in which the six beams are combined together. When the paths of the individual beams are matched to an accuracy of less than one micron, after the light... More »

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